It was fast in London. Now it thinks. Not dramatically — it has not ground to a halt or started displaying alarming messages. It just takes a moment longer than it used to. The spinning beachball makes occasional appearances. Apps take a beat to open. Switching between windows feels slightly reluctant.
This is the most common complaint I hear in Lagos. And it has a surprising number of possible explanations, not all of them requiring my involvement.
Here is a field guide to Mac slowness, ranked from the obvious and entirely self-serviceable to the genuinely worrying.
Level 1: The Obvious — Check These First, Alone, With a Coffee
Too many browser tabs. Each open tab in Safari or Chrome consumes memory. Forty tabs is not browsing. It is a lifestyle, and your Mac is subsidising it. Close the ones you are not using. The ones you are "saving for later" — you are not going back to them. Close those too.
The Mac has not been restarted in weeks. Restart it. Not sleep — restart. This clears memory, closes background processes, and installs any pending updates. It takes three minutes and fixes an embarrassingly high percentage of slowness complaints.
The startup disk is nearly full. Apple Menu → About This Mac → Storage. If the bar is mostly full, your Mac is struggling. macOS needs free space to operate — roughly 10-15% of the total drive capacity. Delete things. Start with downloads, duplicate photos, and applications you have not opened since 2019.
Level 2: The Less Obvious — Worth Investigating
Something is using all the processor. Open Activity Monitor (search for it in Spotlight). Click CPU. Sort by % CPU descending. If something you do not recognise is consuming 80% of your processor, that is your problem. Sometimes it is a legitimate process doing something intensive. Sometimes it is not.
macOS is out of date. Apple regularly releases performance improvements alongside security updates. System Settings → General → Software Update. If there is an update available, install it.
Login items have accumulated. Every application that opens at startup slows down the boot process and often stays running in the background. System Settings → General → Login Items. Review and remove anything unnecessary.
Level 3: The Potentially Worrying — Call Someone
The drive is making unusual sounds. MacBooks with traditional spinning hard drives — less common now, but some older models still have them — can develop mechanical faults that manifest as slowness. If you hear clicking or grinding, stop using the Mac and call immediately. This is a data loss situation developing.
The Mac is running hot all the time. Heat throttling, as covered in a previous note, causes artificial slowness. If your Mac is perpetually warm and the fan is permanently working, the slowness and the heat are connected. This needs a health check.
The slowness appeared suddenly after a specific event. An update, a new application, a file download. Sudden onset slowness is diagnostic — it points to a specific cause rather than gradual wear, and identifying that cause is considerably faster with the right tools.
The mystery of the extremely slow Mac — Lagos marina, 2025
He had tried everything. Restarted. Updated. Deleted half his downloads folder. The Mac remained resolutely slow — particularly when connected to the marina's WiFi.
The cause, when found, was a backup application that had been set to run continuously and was uploading several hundred gigabytes of data to a cloud service over the marina's modest connection, using the majority of both the network bandwidth and the processor to do so.
Turning off continuous backup and scheduling it for overnight reduced his Mac's perceived slowness to zero. The marina's WiFi also became noticeably faster for everyone else on the network.
Mac still slow after all of the above?
There is a cause. There is always a cause. Finding it is what I do. A Mac diagnostic in Lagos takes less than an hour and answers the question definitively. Same day, in your language.
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